High-strength sculptured gypsum. Plaster stucco molding

Architectural elements for finishing facades and interiors, they are now offered to us on the market in a wide range. In order to have a good understanding of the range of architectural elements and correctly evaluate this or that decorative element, it is advisable to know all the materials from which they are made, their advantages and disadvantages.

Let's look at the most common materials from which they are made today, which can be used for exterior and interior decoration of buildings.

Architectural elements: plaster or polystyrene foam?

Classic plaster stucco in its form is made entirely of gypsum. Gypsum is a mineral that is formed as a result of the death of various microorganisms. Stucco, which is made from plaster, is usually very expressive. After all, a sculptor working with plaster will be able to make absolutely all his fantasies come true. But gypsum is heavy, which limits its use in modern construction and decoration. In terms of time and cost of work with gypsum, it is also inferior to the new decorative material - expanded polystyrene!

They are distinguished by the exceptional cleanliness of their surface. Foam products can very accurately convey the structure of even the smallest details without losing their strength characteristics. And the weight of such products is very small along with great strength, which allows the use of stucco decor in the most daring solutions, even with the use of hanging architectural elements big size.

Today, stucco foam is a top seller. This most popular and affordable type of decor has great prospects, thanks to its light weight of parts and the ease of processing the foam from which the decor is made. It is now possible to make architectural elements of various configurations and sizes from polystyrene foam, quickly, efficiently and inexpensively!

Gypsum has been known since ancient times, but has not yet lost its popularity; even many modern materials cannot compete with it. It is used in the construction, porcelain, ceramics, petroleum and medicine industries.

Description of building material

Gypsum is produced from gypsum stone. To obtain gypsum powder, the stone is fired in rotary kilns and then ground to form a powder. Gypsum is most common in construction.

Walls plastered with gypsum mortar are able to absorb excess moisture and release it when the air is too dry.

Gypsum formula

The name gypsum comes from the Greek word gipsos. This material belongs to the class of sulfates. Its chemical formula is CaSO4?2H2O.

There are two types of gypsum:

1. Fibrous - selenite;
2. Grainy - alabaster.

Photos of gypsum varieties

Selenite Alabaster

Technical characteristics and properties

All gypsum mixtures have very similar technical characteristics; let us dwell on the properties and features of building gypsum.

These include:

• Density. Gypsum has a dense, fine-grained structure. The true density is 2.60-2.76 g/cm?. When loosely poured, it has a density of 850-1150 kg/m2, and when compacted, the density is 1245-1455 kg/m2.
• How long does it take to dry? The advantages of gypsum include rapid setting and hardening. The gypsum sets in the fourth minute after mixing the solution, and after half an hour it completely hardens. Therefore, the finished gypsum solution must be used immediately. To slow down the setting, water-soluble animal glue is added to the plaster.
• Specific gravity. Is the specific gravity of gypsum measured in kg/m? in the MKGSS system. Since the ratio of mass is equal to the volume it occupies, the specific, volumetric and bulk weight of gypsum is approximately the same.
• What temperature can it withstand? t melting). Gypsum can be heated to 600-700°C without destruction. The fire resistance of gypsum products is high. Their destruction occurs only six to eight hours after exposure to high temperature.
• Strength. Construction gypsum has a compressive strength of 4-6 MPa, high-strength - from 15 to 40 MPa or more. Well-dried samples have two to three times higher strength.
• GOST State standard of gypsum 125-79 (ST SEV 826-77).
• Thermal conductivity. Gypsum is a poor conductor of heat. Its thermal conductivity is 0.259 kcal/m deg/hour in the range from 15 to 45°C.
• Solubility in water. R dissolves in small quantities: 2.256 g dissolves in 1 liter of water at 0°, 2.534 g at 15°, 2.684 g at 35°; with further heating, the solubility decreases again.

The video talks about building gypsum and how you can improve its properties by giving additional strength:

Types of gypsum

Gypsum has the greatest variety of applications among other binding materials. It allows you to save on other materials. There are many varieties of gypsum.

Building

It is used for the production of gypsum parts, partition slabs for plastering work. Work with gypsum mortar must be carried out in a very short time - from 8 to 25 minutes, it depends on the type of gypsum. During this time it must be completely used up. When hardening begins, gypsum already gains about 40% of its final strength.

Since cracks do not form in the gypsum during hardening, when mixing the mortar with lime mortar, which gives it plasticity, you do not need to add various fillers. Due to the short setting time, hardening retarders are added to gypsum. Construction gypsum reduces labor intensity and construction costs.

In deposits by blasting gypsum-containing rock. The ore is then transported to factories in the form of gypsum stones.

High strength

The chemical composition of high-strength gypsum is similar to building gypsum. But building gypsum has smaller crystals, while high-strength gypsum has large crystals, so it has less porosity and very high strength.

High-strength gypsum is produced by heat treatment in a sealed apparatus into which gypsum stone is placed.

The scope of application of high-strength gypsum is extensive. Various building mixtures are prepared from it and fireproof partitions are built. It is also used to make various molds for the production of porcelain and earthenware sanitary ware. High-strength gypsum is used in traumatology and dentistry.

Polymeric

Orthopedic traumatologists are more familiar with synthetic polymer plaster; plaster bandages are produced on its basis for applying bandages for fractures.

Advantages of polymer plaster casts:

1. three times lighter than conventional plaster;
2. easy to apply;
3. allow the skin to breathe, as they have good permeability;
4. resistant to moisture;
5. allow you to control bone fusion, as they are permeable to x-rays.

Cellacast

Bandages are also made from this plaster; their structure allows the bandage to be stretched in all directions, so very complex bandages can be made from it. Cellacast has all the properties of a polymer bandage.

Sculpted or molded

This is the most highly durable gypsum, it does not contain any impurities, it has high natural whiteness. It is used for making molds for sculptures, plaster figurines, sculpting souvenirs, in the porcelain and earthenware, aviation and automotive industries.

This is the main component of dry putty mixtures. Molding gypsum is obtained from building gypsum, for this it is additionally sifted and ground.

Known for several centuries, it still remains relevant in our time. The most common rosettes are gypsum, they are easy to make with your own hands.

Acrylic

Acrylic plaster is made from water-soluble acrylic resin. After hardening, it looks similar to regular plaster, but is much lighter. Ceiling stucco and other decorative details are made from it.

Acrylic gypsum is frost-resistant and has little moisture absorption, so it can be used to decorate building facades, creating interesting design solutions.

Working with acrylic plaster is very simple. If you add a little marble chips or aluminum powder or other inert fillers to the solution, acrylic plaster products will closely resemble marble or metal ones.

This is what acrylic plaster looks like

Polyurethane

Gypsum stucco can also be made from polyurethane or polystyrene gypsum. It costs much less than ordinary gypsum, and its qualities are almost no different from it.

White

Using white gypsum, seams and cracks are sealed, stucco is made and other types of construction and repair work are carried out. It is compatible with various types of building materials. White gypsum hardening time 10 minutes.

Fine grain

Fine-grained gypsum is also called translucent. It is used to fill seams, joints in slabs, etc.

Liquid

Liquid gypsum is prepared from gypsum powder.

It is prepared using the following technology:

• Pour water in the required quantity.
• Pour in gypsum and mix immediately.
• The density of the solution can be varied. A liquid solution is made to fill the molds

Waterproof (moisture resistant)

Waterproof gypsum is obtained by processing raw materials using a special technology. To improve the properties of gypsum, stillage, a waste product from the production of ethyl alcohol, is added to it.

Refractory

Gypsum is a non-flammable material and is not flammable, but plasterboard sheets made from it are quite flammable. To give them fire resistance, tongue-and-groove gypsum is used. It is used wherever it is required to increase fire resistance.

Architectural

Architectural gypsum does not contain toxic components, it is very plastic. Its acidity is similar to that of human skin. Classic modeling from architectural plaster is very popular among designers; there is a very high demand for it.

It requires certain knowledge, so you should first carefully study the features of such work, and only then proceed to practice.

Stamps

Plaster marking is carried out after testing standard samples of sticks for bending and compression two hours after they are molded. According to GOST 129-79, twelve grades of gypsum are established, with strength indicators from G2 to G25.

Plaster substitute

An analogue of gypsum is a finely dispersed grayish-white powder - alabaster. It is also popular in construction. Alabaster is obtained from natural gypsum dihydrate by heat treatment at temperatures from 150 to 180? C. Externally, alabaster and gypsum are no different from each other.

Alabaster is used to plaster walls and ceilings at low indoor humidity. Gypsum panels are produced from it.

What is the difference between plaster and alabaster?

Gypsum and alabaster have the following differences:

1. Alabaster is more limited in application, as it is used only in the construction industry. Gypsum is also used in medicine.
2. Alabaster dries instantly, so it is not suitable without the addition of special substances.
3. Gypsum is safer for the environment and human health.
4. Alabaster has greater hardness than gypsum.

The online store of building materials "MasterSmesi" offers to evaluate high-strength gypsum G-16, which is often called sculptural or architectural. Its strength indicator is 160 kg/cm 2. In addition, G-16 gypsum has a fine grind, which makes it suitable for decorative finishing.

Areas of application of G-16 gypsum

• production of dry construction mixtures;
• production of artistic details for the home (decorative plates, cornices, bas-reliefs, sculptures, etc.);
• production of molds in the ceramic industry;
• in medicine (traumatology and dentistry).

You have delicate, neat finishing work ahead of you, you need to work on the design of your house, then G-16 gypsum will be an ideal assistant for you.

A product unique in its properties, which is used both for construction and for the manufacture of stucco molding. Gypsum G-16, like construction gypsum, has astringent properties. The G-16 has found wide use among the people. It is often used for grouting putties, primers and for sealing seams.

Construction gypsum is a fine powder of extremely white or light gray color, obtained by grinding and firing (or exactly the opposite - firing and grinding) natural gypsum stone. The advantage of this material over others is its very fast setting and the same hardening.

The beginning of setting occurs within 5 minutes after its application. In some cases, these advantages can turn into disadvantages, therefore, to slow down the setting and hardening reactions, lime mortar, water-soluble animal glue, etc. are added to it.

Areas of application of gypsum in construction

During the hardening process, this material is capable of increasing in volume, which is characteristic only of prestressing cements, but, unlike the latter, our object of discussion is a fairly light material and can be used in interior finishing work.

Its undeniable advantages include environmental friendliness, non-flammability, and the ability to “breathe”. The disadvantage of the building material is its relatively low strength and water resistance; in addition, it is quite easy to scratch.

This material is used for finishing plastering work, the manufacture of any products, drywall, molds, castings, as an additive to other binders, wood concrete, for ventilation ducts, etc.

Also, chemically or using traditional technology, they obtain high-strength gypsum. This is a material of the highest quality, used where all its unique characteristics are needed, and the strength of ordinary building gypsum is not enough.

Types of gypsum - why is there such diversity?

This material has a large number of varieties. And each has found its practical application in life. There are the following types of gypsum:

• Pure material combined with a mixture of lime and blast furnace slag is called waterproof plaster. In addition, to increase the water resistance of products, surface-active organic additives (sulfite-alcohol stillage) can be added to its composition. And the use of an aqueous solution of certain resins (carbamyl), in the form of a mixing liquid, can provide fairly high levels of mechanical strength and water resistance;
• Lightweight plaster obtained by using special technologies in the process of processing conventional raw materials. This material is used in the manufacture of high-quality ceiling moldings and wall panels;
• When the raw material is heated to approximately 140 °C, it turns into a white or grayish powder. This material is perfectly soluble in water, it is used for the manufacture of high-strength, construction and other gypsum compositions. We can say that the received semi-aqueous gypsum– this is a semi-finished product for further processing of this material;
• Raw ground gypsum used as an additive in the production of cellular concrete, aerated concrete, and for soil treatment.
• Fine-grained gypsum needed in construction for filling joints, joining slabs, finishing, etc. This material is also called a translucent type of gypsum. It is part of construction alabaster;
• Architectural plaster, another name is molding, intended for the production of stucco molding, decorative stone, restoration of building facades, production of souvenirs and various forms.

The above examples are not all types of gypsum, but, as can be seen from what is written, it has firmly and permanently entered many areas of construction. This is due to its excellent characteristics and environmental friendliness.